XP doesn't come with ASPI as standard, it comes with SPTI which it uses by default. Express Rip will always use SPTI over ASPI if the former is detected on your system. If you like, contact me at tj[at]nch.com.au to request an ASPI version of Rip.
FYI: SPTI works perfectly fine, only a small minority of customers report problems with it, and we found from experience this is due to problems with either the CD-ROM drivers or the CD-ROM hardware. Customers have, for example, reported Rip doesn't work on their computer, only to buy new hardware and have it work fine on the new hardware (I'm not saying you buy new hardware, just giving an example).